Diagnostic reasoning model validation in digestive endoscopy

The development of a computer-assisted diagnostic system in digestive endoscopy implies to understand the reasoning process of endoscopists. The aim of this study is to validate a reasoning model and a knowledge base previously defined. Eight endoscopists have participated to a diagnostic test including 5 video-sequences and using a "thinking aloud" method. The physician discourse was compared with the knowledge base contents Forty requests, built with indices extracted from endoscopist talks were submitted to the diagnostic research system. The main results show that the endoscopists evoke all the information types defined in the knowledge base. Endoscopists well distinguish the endoscopic findings and diagnoses. They combine data-driven and hypothesis-driven approaches during the diagnostic process. Faced to complex diagnostic problem solving, they promote an analytical approach. The 40 requests have led to the correct finding class, as unique or first response in 25, second or other rank response in 12, and failed to recognize the lesion in 3 cases. These results are consistent with the reasoning model and the knowledge base content They suggest several ways for improving the diagnostic aid system, the research approach as well as the user interface.